(Right to left) Dany Noswis and Orbey Casta–eda are former paramilitaries who are now participating in the Peace and Reconciliation Program in Medellin, Colombia. They are both working towards their high school degrees and attend weekly training sessions in their barrio, La Moravia, in the center of Medellin.

The first year that Dany Noswis spent with right-wing paramilitaries in Colombia he was panicked and homesick. He was 19 when he left without telling his family, drawn by money.

In the next five years he spent as a paramilitary, he says, he saw enough killing and cruelty to haunt his dreams for decades to come. "So many people had nothing to do with this war," he says ruefully.

When Colombia demobilized paramilitaries, beginning in 2003, scores of young men like Mr. Noswis headed home, many to the rough neighborhoods from which they fled or were initially recruited, and joined the Peace and Reconciliation program run by the city of Medellín.

"They are giving us the opportunity to be a real person in life," Noswis says during a weekly group session, this one on democracy. "Today I am a person who does not hurt anyone."